British historian Michael Howard observed long ago that during extended eras of peace, military planners are like sailors. He meant true sailors, those who use sextants and abhor the Global Positioning System. Likewise, military leaders must navigate into the future without crystal balls, using "dead reckoning" off of small conflicts and technical advances to gauge the nature of the next enemy and the next war.

http://www.armedforcesjournal.com/2006/03/1813952